USAID FOR EDUCATION
Everyone will tell you that if you don't know it, it is too late to learn. They are wrong! They are talking about long-term memory. You will be using short-term memory.
As you are sitting outside the exam room study your formulae, or dates, or anything else that you have difficulty remembering. Whenever the examiner says that you can start writing, write down all these things on scrap paper. You have managed to remember them for ten minutes. You can now forget them until you need them again, which may be never.